Point Arena Mountain Beaver by Elizabeth Whisler

Saving the Point Arena Mountain Beaver

What is the Point Arena Mountain Beaver?

            The Aplodontia rufa nigra, or the Point Arena Mountain Beaver, is one of the seven subspecies of mountain beavers ranging in the Pacific Northwest that have a lifespan of five to six years. They weigh between two and four pounds and are around one foot in length. They are compact, stout, and somewhat cylindrical in shape and possess a laterally compressed, broad skull. Their coloring is darker and blackish unlike in other species of beaver. They are semi-fossorial and stay in their underground burrows the majority of the time. When they do come up it's for the purpose of foraging on the surrounding vegetation for their herbivorous diet. The ratio of males to females is 1:1 and their breeding season is from mid-December to late June and dispersal occurs from mid-April to late September. Females will begin breeding at two years old and birth one litter a year consisting of two or three offspring, which shows their relatively low reproductive output. The most important factors for their habitat consist of a cool thermal regime, adequate soil drainage and softness, an abundant food supply, and a high cover of woody plants. 

            Geographic and Population Changes

            Lead Region: California/Nevada region

            Mountain beavers appear in many areas around the Pacific Northwest (Fig. 1), however the Point Arena subspecies is found in only a 24 sq. mi. coastal area in western Mendocino County in California (Fig. 2). There are only 26 separate populations of this mountain beaver with an estimated total population of 200 to 500 beavers.

Figure 1.  Global range of the Mountain Beaver, Aplodontia rufa, shown in dark grey

Figure 2. Global range of the Point Arena Mountain Beaver, Aplodontia rufa nigra, shown in red

            Listing Date and Type of Listing

            Date Listed: December 12, 1991

            Endangered

            Final Plan - Published June 2, 1998

            Cause of listing and Main threats to its continued existence

            The cause of listing was because of the sharp decline in population. Main threats include urban development, land being used for agriculture, and construction of transportation and utility facilities. Livestock also has an effect by altering vegetation and causing their burrows to collapse or be crushed. Other threats include invasive plants, domestic pets, rodent control, pesticides, vehicles, vegetation fires, and timber harvesting. The last example is a problem because they are extremely sensitive to vibrations and loud noises.

            Recovery Plan

            Actions Needed:

            1. Protect known populations.

                     2. Protect suitable habitat, buffers, and corridors.

                     3. Develop management plans and guidelines.

                     4. Gather biological and ecological data necessary for conservation of the subspecies.

                     5. Determine feasibility of, and need for, relocation.

                     6. Monitor existing populations and survey for new ones.

                     7. Establish an outreach program.

                    
                     Estimated Cost of Recovery:

                    

                     $1,047.000±.The total cost of this conservation effort may be higher than this prediction since some costs for various tasks needed for recovery have not been determined.

                     What can you do?

            There are many ways in which you can help the conservation of the Point Arena Mountain Beaver. These include:

            When buying wood, make sure it's not from this beaver's habitat.

            If out in nature in this area, make sure to be aware of the beaver and be careful to not disturb it or it's burrows.

            Do not use either rat poison or pesticides in your home.

            Call or contact your local government to push for the hunting of this beaver to become illegal.

                     For More Information Visit These Sites!

https://soundwaves.usgs.gov/2005/04/research2.html

                     http://www.iucnredlist.org/details/1869/0
            https://www.registrelep-sararegistry.gc.ca/default.asp?lang=En&n=C2F75916-1

            References

                     "Point Arena Mountain Beaver Species Profile." U.S Fish and Wildlife. Arcata Fish and Wildlife Service, 11 Apr. 2011. Web. 04 June 2015.<http://www.fws.gov/arcata/es/mammals/mtnBeaver/mtnbeaver.html>.

                     U.S. Fish and Wildlife Service. 1998. Point Arena Mountain Beaver (Aplodontia ru/a nigra(Rafinesque) Recovery Plan. Region 1, Portland, OR. 71 pp.